Many of you ask me about the possibility of making curved cuts with the diy table jigsaw, the one I made by attaching the jigsaw tool upside down under a board. In some woodworking projects you have already seen me cutting curves and more or less wide circles with the jigsaw table, including a sheet metal circle of about 20cm radius. But since I think the question is about the possibility of making more sharp curved cuts, such as those made with a scroll saw, I decided to do a test with some narrow jigsaw blades for curved cuts that I have in my shop.
For this test with the table jig saw I used three of those narrower blades that are supposed to be specially designed for making curved cuts in wood.
Specifically I will used one narrow jigsaw blade from Wolfcraft, a cheap one, and another one that I think is from Bosh, but I’m not sure. The Wolfcraft jigsaw blade has a straight tooth tip and the characteristic set with the typical alternated bended teeth. The cheap jigsaw blade and the other unbranded one are exactly the same, and the only difference between them may be the quality of the metal they are made of, which is difficult to tell at a glance. These two narrow jigsaw blades have half-pyramid-shaped and straight teeth.
Since these jigsaw blades are not very long, at the bottom of the back-and-forth motion the tip of the blade is below the surface of the jigsaw table top, but even so they can still cut the workpiece we slide and cut on the table top, although as we will see they sometimes hit the wood underneath.
At first, with the narrow Wolfcraft jigsaw blade it seemed that cutting sharp curves was possible, since due to the bended teeth setting it makes a wider kerf and that reduces the friction of the jig saw blade against the sides of the kerf. But after forcing the curved cut to make a more tight cut with the three blades, the result is always that the jigsaw blade gets too hot due to friction, and the wood burns and even smokes.
And due to the heat generated by the friction against the wood when cutting tight curves, the cutting blade even shows those characteristic bluish colors that are left on metals that have been overheated. In short, if we want to cut tight curves like those obtained with a scroll saw, we will need a scroll saw.
And since I was testing with my table jigsaw, in addition to cutting curves I also made a few small straight cuts to compare the three narrow jigsaw blades. As expected, the Wolfcraft blade with its bended teeth setting makes a wider cut, and its straight tip teeth cause more chipping on both sides of the plywood. The other two jigsaw blades, being practically the same, make a very similar and much cleaner cut thanks to the sharper shape of the teeth, and they make a narrower slot because the teeth are straight and not alternatively bended to the sides.
However, the blade which I believe is from Bosh, perhaps due to the fact that it may be very slightly bend longwise, hits the wood underneath. Always on the same side of the cut. However, this would not happen if the tip of the blade always remains above the tabletop of the table jigsaw during the entire back-and-forth motion of the jigsaw blade. The cheap jigsaw blade seems to cut just as well as the “Bosh” blade, but if the metal is not of the same quality, if it is a worse quality jigsaw blade, it will stop cutting well much sooner.
You may have already noticed that I don’t usually buy the best quality power tools, since the “medium” quality ones give me pretty good results for the use I give them (I’m not saying that a good quality tool is not worth it. On the contrary. But until now I could not afford them and with the medium quality tools I could make my woodworking and DIY projects well). But lately I try to buy better quality tools both to attach to the DIY machines I make or to use by hand, since the cutting quality is much better than with cheap tools. And these quality tools can make too much more amount of work before needing to be sharpened.